scholarly journals The Role of Microglial Phagocytosis in Ischemic Stroke

2022 ◽  
Vol 12 ◽  
Author(s):  
Junqiu Jia ◽  
Lixuan Yang ◽  
Yan Chen ◽  
Lili Zheng ◽  
Yanting Chen ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Apoptotic Cell ◽  
Neurological Deficits ◽  
Specific Cell ◽  
Microglial Polarization ◽  
Microglial Phagocytosis ◽  
Injured Brain ◽  
Tissue Reconstruction ◽  
The Central Nervous System

Microglia are the resident immune cells of the central nervous system that exert diverse roles in the pathogenesis of ischemic stroke. During the past decades, microglial polarization and chemotactic properties have been well-studied, whereas less attention has been paid to phagocytic phenotypes of microglia in stroke. Generally, whether phagocytosis mediated by microglia plays a beneficial or detrimental role in stroke remains controversial, which calls for further investigations. Most researchers are in favor of the former proposal currently since efficient clearance of tissue debris promotes tissue reconstruction and neuronal network reorganization in part. Other scholars propose that excessively activated microglia engulf live or stressed neuronal cells, which results in neurological deficits and brain atrophy. Upon ischemia challenge, the microglia infiltrate injured brain tissue and engulf live/dead neurons, myelin debris, apoptotic cell debris, endothelial cells, and leukocytes. Cell phagocytosis is provoked by the exposure of “eat-me” signals or the loss of “don’t eat-me” signals. We supposed that microglial phagocytosis could be initiated by the specific “eat-me” signal and its corresponding receptor on the specific cell type under pathological circumstances. In this review, we will summarize phagocytic characterizations of microglia after stroke and the potential receptors responsible for this programmed biological progress. Understanding these questions precisely may help to develop appropriate phagocytic regulatory molecules, which are promoting self-limiting inflammation without damaging functional cells.

scholarly journals The Role of Alpha-Lipoic Acid in the Pathomechanism of Acute Ischemic Stroke

2018 ◽  
Vol 48 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Qingqing Wang ◽  
Chengmei Lv ◽  
Yongxin Sun ◽  
Xu Han ◽  
Shan Wang ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Lipoic Acid ◽  
Nuclear Translocation ◽  
Infarct Volume ◽  
Neurological Deficits ◽  
Experimental Stroke ◽  
Enzyme Linked Immunosorbent Assay ◽  
M2 Phenotype

Background/Aims: Ischemic stroke results in increased cerebral infarction, neurological deficits and neuroinflammation. The underlying mechanisms involving the anti-inflammatory and neuroprotective properties of α-Lipoic acid (α-LA) remain poorly understood. Herein, we investigated the potential role of α-LA in a middle cerebral artery occlusion (MCAO) rat model and an in vitro lipopolysaccharide (LPS)-induced microglia inflammation model. Methods: In the in vivo study, infarct volume was examined by TTC staining and Garcia score was used to evaluate neurologic recovery. The cytokines were evaluated by enzyme-linked immunosorbent assay, and protein expression of microglia phenotype and NF-κB were measured using western blot. In the in vitro study, the expressions of microglia M1/M2 phenotype were evaluated using qRT-PCR, and immunofluorescence staining was used to assess the nuclear translocation of NF-κB. Results: Both 20 mg/kg and 40 mg/kg of α-LA alleviated infarct size, brain edema, and neurological deficits. Furthermore, α-LA induced the polarization of microglia to the M2 phenotype, modulated the expression of IL-1β, IL-6, TNF-α and IL-10, and attenuated the activation of NF-κB after MCAO. α-LA inhibited the expression of M1 markers, increased activation of the M2 markers, and suppressed the nuclear translocation of NF-κB in LPS-stimulated BV2 microglia. Conclusions: α-LA improved neurological outcome in experimental stroke via modulating microglia M1/M2 polarization. The potential mechanism of α-LA might be mediated by inhibition of NF-κB activation via regulating phosphorylation and nuclear translocation of p65.

scholarly journals Migration of Self-Introduced Acupuncture Needle into the Brainstem

2018 ◽  
Vol 09 (03) ◽  
pp. 434-436
Author(s):  
Shadi El-Wahsh ◽  
Johnny Efendy ◽  
Mark Sheridan
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Conservative Management ◽  
Foreign Bodies ◽  
Neurological Deficits ◽  
Acupuncture Needle ◽  
Surgical Extraction ◽  
The Central Nervous System ◽  
Operative Assessment

ABSTRACTAcupuncture-related injuries to the central nervous system are a rare but well-documented occurrence. This report describes the case of a self-introduced acupuncture needle migrating into the brainstem following an initial failed attempt at surgical extraction. The patient displayed no neurological deficits, and the needle was eventually successfully removed under direct vision intraoperatively. We discuss the role of various imaging modalities in pre- and post-operative assessment of penetrating foreign bodies in the brainstem. We also discuss the options available for the management of such foreign bodies, including possible approaches for operative intervention, and the risks involved with both surgical and conservative management.

Abstract WP96: The Role of T-Lymphocytes in Neuroregeneration After Cerebral Ischemia

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Kai Diederich ◽  
Antje Schmidt ◽  
Jan-Kolja Strecker ◽  
Wolf-Rüdiger Schäbitz ◽  
Jens Minnerup
Keyword(s):  
T Cells ◽  
Ischemic Stroke ◽  
Adoptive Transfer ◽  
Critical Role ◽  
Chronic Phase ◽  
Cognitive Testing ◽  
Neurological Deficits ◽  
Ischemic Brain ◽  
Immunodeficient Mice

Introduction: Inflammation plays a critical role in the pathogenesis of ischemic stroke. The CNS responds to ischemic injury with an inflammatory process, characterized by an infiltration of inflammatory cells. Particularly T cells exhibit a great impact on early stroke outcome as recent studies showed that ablation of these cells decrease infarct size and improve neurological deficits in the acute phase after stroke. However, the role of T cells in the sub-acute and chronic phase after stroke is unknown. T cells are essential for effective neurogenesis and angiogenesis, mechanisms that are integral for successful regeneration after stroke. We assessed the hypothesis that T cells influence cellular mechanisms of post-ischemic neuroregeneration and consequently affect functional and structural recovery. Methods: 24 wild type (wt) and 11 RAG1 -/- mice were subjected to photothrombotic ischemia, a subset of 12 wt and 6 RAG1 -/- animals underwent training in motorized running wheels starting at day 3 following ischemia until the end of the experiment on day 28. Sensorimotor and cognitive testing was applied to quantify the recovery process. To label newly generated neurons, 5-Chloro-2′-deoxyuridine (CldU) and iododeoxyuridine (IdU) were administered at days 1 and 2 (CldU) and once weekly until day 28 (IdU) after ischemia. In a subsequent experiment, 17 RAG1 -/- mice were subjected to photothrombotic ischemia and underwent training, a subset of 10 animals received an adoptive transfer of T cells. Functional testing and cellular labeling were carried out in analogy to the first experiment. Results: Training improved recovery from sensorimotor and cognitive deficits following cortical ischemia in wt animals and increased the generation of new neurons in the ischemic brain. Rehabilitative training did not induce functional recovery in RAG1 -/- animals and had no effect on the generation of neurons. Adoptive transfer of T cells into the immunodeficient mice restored the ability for regeneration. Conclusion: T cells play an essential role in the functional and structural regeneration following ischemic brain injury. These results provide new clues on the complex mechanism by which immune cells impact different stages of the pathogenesis of ischemic stroke.

Fasudil-Triggered Phagocytosis of Myelin Debris Promoted Meylin Regeneration via the Activation of TREM2/DAP12 Signaling Pathway in Cuprizone-Induced Mice

2021 ◽  
Author(s):  
Zhi-Bin Ding ◽  
Qing-Xian Han ◽  
Li-Juan Song ◽  
Qing Wang ◽  
Guang-Yuan Han ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Animal Experiments ◽  
Demyelinating Diseases ◽  
Phagocytic Capacity ◽  
Microglial Phagocytosis ◽  
M2 Polarization ◽  
M2 Microglia ◽  
Myelin Debris ◽  
The Central Nervous System

Abstract The inflammation and demyelination of the central nervous system (CNS) are mainly involved in multiple sclerosis (MS), in which the disorder of myelin regeneration leads to continual neurologic impairment. Fasudil, one of the ROCK inhibitors, has been shown protective functions in some models of demyelinating diseases. In this study, Fasudil treatment ameliorated the behavioral performance and myelin loss in CPZ-fed mice. Here, we demonstrated a new role of Fasudil, which triggered microglia to uptake myelin debris in both cell and animal experiments. This increased phagocytosis was associated with the polarization of M2 microglia. Furthermore, we found that Fasudil enhanced the expression of triggering receptor expressed on myeloid cells 2 (TREM2) and DNAX-activating protein of 12 kDa (DAP12), which regulated microglial phagocytosis and M2 polarization. The silence of TREM2 effectively blocked Fasudil-triggered phagocytic capacity, suggesting that Fasudil-triggered phagocytosis depends on TREM2 signaling pathway. Based on these evidences that TREM2 regulates microglial M2 polarization and phagocytosis, future studies targeted Fasudil as a therapy for demyelinating and neurodegenerative diseases are warranted.

scholarly journals Pericytes for Therapeutic Approaches to Ischemic Stroke

2021 ◽  
Vol 15 ◽  
Author(s):  
Lu Cao ◽  
Yanbo Zhou ◽  
Mengguang Chen ◽  
Li Li ◽  
Wei Zhang
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Ischemic Stroke ◽  
Therapeutic Target ◽  
Neurological Disorders ◽  
Neurovascular Unit ◽  
Therapeutic Approaches ◽  
Multipotent Cells ◽  
The Central Nervous System

Pericytes are perivascular multipotent cells located on capillaries. Although pericytes are discovered in the nineteenth century, recent studies have found that pericytes play an important role in maintaining the blood—brain barrier (BBB) and regulating the neurovascular system. In the neurovascular unit, pericytes perform their functions by coordinating the crosstalk between endothelial, glial, and neuronal cells. Dysfunction of pericytes can lead to a variety of diseases, including stroke and other neurological disorders. Recent studies have suggested that pericytes can serve as a therapeutic target in ischemic stroke. In this review, we first summarize the biology and functions of pericytes in the central nervous system. Then, we focus on the role of dysfunctional pericytes in the pathogenesis of ischemic stroke. Finally, we discuss new therapies for ischemic stroke based on targeting pericytes.

scholarly journals Dynamic Role of Phospholipases A2 in Health and Diseases in the Central Nervous System

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2963
Author(s):  
Grace Y. Sun ◽  
Xue Geng ◽  
Tao Teng ◽  
Bo Yang ◽  
Michael K. Appenteng ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cellular Localization ◽  
Cell Types ◽  
Molecular Structures ◽  
Specific Cell ◽  
Phospholipases A2 ◽  
Cell Functions ◽  
The Central Nervous System

Phospholipids are major components in the lipid bilayer of cell membranes. These molecules are comprised of two acyl or alkyl groups and different phospho-base groups linked to the glycerol backbone. Over the years, substantial interest has focused on metabolism of phospholipids by phospholipases and the role of their metabolic products in mediating cell functions. The high levels of polyunsaturated fatty acids (PUFA) in the central nervous system (CNS) have led to studies centered on phospholipases A2 (PLA2s), enzymes responsible for cleaving the acyl groups at the sn-2 position of the phospholipids and resulting in production of PUFA and lysophospholipids. Among the many subtypes of PLA2s, studies have centered on three major types of PLA2s, namely, the calcium-dependent cytosolic cPLA2, the calcium-independent iPLA2 and the secretory sPLA2. These PLA2s are different in their molecular structures, cellular localization and, thus, production of lipid mediators with diverse functions. In the past, studies on specific role of PLA2 on cells in the CNS are limited, partly because of the complex cellular make-up of the nervous tissue. However, understanding of the molecular actions of these PLA2s have improved with recent advances in techniques for separation and isolation of specific cell types in the brain tissue as well as development of sensitive molecular tools for analyses of proteins and lipids. A major goal here is to summarize recent studies on the characteristics and dynamic roles of the three major types of PLA2s and their oxidative products towards brain health and neurological disorders.

scholarly journals Microglial phagocytosis dysfunction during stroke is prevented by rapamycin

2021 ◽  
Author(s):  
Sol Beccari ◽  
Virginia Sierra-Torre ◽  
Jorge Valero ◽  
Mikel Garcia-Zaballa ◽  
Alejandro Carretero-Guillen ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Therapeutic Target ◽  
Apoptotic Cell ◽  
Knock Out ◽  
Microglial Phagocytosis ◽  
Cellular Debris ◽  
The Brain

Microglial phagocytosis is rapidly emerging as a therapeutic target in neurodegenerative and neurological disorders. An efficient removal of cellular debris is necessary to prevent buildup damage of neighbor neurons and the development of an inflammatory response. As the brain professional phagocytes, microglia are equipped with an array of mechanisms that enable them to recognize and degrade several types of cargo, including neurons undergoing apoptotic cell death. While microglia are very competent phagocytes of apoptotic cells under physiological conditions, here we report their dysfunction in mouse and monkey (Macaca fascicularis and Callithrix jacchus) models of stroke by transient occlusion of the medial cerebral artery (tMCAo). The impairment of both engulfment and degradation was related to energy depletion triggered by oxygen and nutrients deprivation (OND), which led to reduced process motility, lysosomal depletion, and the induction of a protective autophagy response in microglia. Basal autophagy, which is in charge of removing and recycling intracellular elements, was critical to maintain microglial physiology, including survival and phagocytosis, as we determined both in vivo and in vitro using knock-out models of autophagy genes and the autophagy inhibitor MRT68921. Notably, the autophagy inducer rapamycin partially prevented the phagocytosis impairment induced by tMCAo in vivo but not by OND in vitro. These results suggest a more complex role of microglia in stroke than previously acknowledged, classically related to the inflammatory response. In contrast, here we demonstrate the impairment of apoptotic cell phagocytosis, a microglial function critical for brain recovery. We propose that phagocytosis is a therapeutic target yet to be explored and provide evidence that it can be modulated in vivo using rapamycin, setting the stage for future therapies for stroke patients.

scholarly journals Activation and Role of Astrocytes in Ischemic Stroke

2021 ◽  
Vol 15 ◽  
Author(s):  
Xin-Ya Shen ◽  
Zhen-Kun Gao ◽  
Yu Han ◽  
Mei Yuan ◽  
Yi-Sha Guo ◽  
...  
Keyword(s):  
Nervous System ◽  
Ischemic Stroke ◽  
Protective Role ◽  
Reactive Astrocytes ◽  
High Morbidity ◽  
Temporal Expression ◽  
The Central Nervous System ◽  
Controversial Topic ◽  
And Function

Ischemic stroke refers to the disorder of blood supply of local brain tissue caused by various reasons. It has high morbidity and mortality worldwide. Astrocytes are the most abundant glial cells in the central nervous system (CNS). They are responsible for the homeostasis, nutrition, and protection of the CNS and play an essential role in many nervous system diseases’ physiological and pathological processes. After stroke injury, astrocytes are activated and play a protective role through the heterogeneous and gradual changes of their gene expression, morphology, proliferation, and function, that is, reactive astrocytes. However, the position of reactive astrocytes has always been a controversial topic. Many studies have shown that reactive astrocytes are a double-edged sword with both beneficial and harmful effects. It is worth noting that their different spatial and temporal expression determines astrocytes’ various functions. Here, we comprehensively review the different roles and mechanisms of astrocytes after ischemic stroke. In addition, the intracellular mechanism of astrocyte activation has also been involved. More importantly, due to the complex cascade reaction and action mechanism after ischemic stroke, the role of astrocytes is still difficult to define. Still, there is no doubt that astrocytes are one of the critical factors mediating the deterioration or improvement of ischemic stroke.

scholarly journals MiR-298 Exacerbates Ischemia/Reperfusion Injury Following Ischemic Stroke by Targeting Act1

2018 ◽  
Vol 48 (2) ◽  
pp. 528-539 ◽  
Author(s):  
Hongxue Sun ◽  
Di Zhong ◽  
Cheng Wang ◽  
Yilei Sun ◽  
Jiaying Zhao ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Artery Occlusion ◽  
Neurological Deficits ◽  
Luciferase Assay ◽  
Regulatory Relationship

Background/Aims: This study investigated the role of the microRNA miR-298 and its target Act1 in ischemic stroke. Methods: Cell viability was assessed with the 3-(4,5-dimethythiazol-2- yl)-2,5-diphenyl tetrazolium bromide assay. Apoptotic cells were detected by flow cytometry, and mRNA and protein expression were assessed by quantitative real-time PCR and western blotting, respectively. The regulatory relationship between miR-298 and Act1 was evaluated with the luciferase assay. To clarify the role of Act1 following ischemic stroke, the transcript was knocked down by short interfering RNA. The in vitro findings were validated in a mouse model of middle cerebral artery occlusion by administration of miR-298 mimic. Results: Act1 was upregulated whereas miR-298 was downregulated in ischemic stroke. miR-298 overexpression by transfection of a mimic suppressed Act1 protein levels in vitro and in vivo, and the luciferase assay showed that miR-298 directly binds to the 3’ untranslated region of the Act1 transcript. miR-298 overexpression enhanced cell apoptosis and autophagy and exacerbated ischemic infarction and neurological deficits, effects that were exerted via negative regulation of Act1/c-Jun N-terminal kinase (JNK)/nuclear factor (NF)-κB signaling and downstream autophagy pathways. Conclusions: Upregulation of miR-298 following ischemic stroke promotes brain injury in vitro and vivo by inhibiting the Act1/JNK/NF-κB signaling cascade and the downstream autophagy pathway. Therapeutic strategies that target miR-298 could be beneficial for the treatment of ischemic stroke.

scholarly journals Peran Ferritin pada Stroke Iskemik Akut

2021 ◽  
Vol 10 (2) ◽  
pp. 127-132
Author(s):  
Lisda Amalia ◽  
Keyword(s):  
Oxidative Stress ◽  
Ischemic Stroke ◽  
Iron Homeostasis ◽  
Cell Damage ◽  
The Body ◽  
Neurological Deficits ◽  
Iron Storage ◽  
The Central Nervous System ◽  
Focal Injury ◽  
Iron Storage Protein

Stroke is a neurological deficit that occurs due to acute focal injury to the central nervous system that occurs solely due to vascular disorders, including cerebral infarction or bleeding. Ferritin is an intracellular and extracellular iron storage protein which is essential for iron homeostasis in the body. Ferritin is expressed in microglia and macrophages, and also in neurons. If there is cell damage due to ischemic stroke, ferritin will leave the cells and enter the serum. The hypoxia-ischemic state in stroke induces the expression of ferritin in oligodendrocytes and microglia. When there is oxidative stress, ferritin formation will increase. The function of ferritin in times of oxidative stress is still controversial. Ferritin in this condition can act as a scavenger and as a donor for free iron ions. Ischemic stroke patients with larger lesions and more severe neurological deficits showed higher serum ferritin levels and a higher likelihood of complications of bleeding transformation.

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